Fingolimod protects against cerebral ischemia reperfusion injury in rats by reducing inflammatory cytokines and inhibiting the activation of p38 MAPK and NF-κB signaling pathways
Introduction
Cerebral ischemia–reperfusion injury is a therapeutic challenge for treatment of ischemic brain damage [33] and reperfusion exacerbates cerebral injury causing brain cell death. Drugs for cerebral ischemia–reperfusion injury have been attracted increasing attention in recent years. Fingolimod (FTY720), a new type of immunosuppressive agent, is approved for the treatment of multiple sclerosis (MS) by United States food and drug administration (FDA) in 2010 [9], [27]. Previously, it has been reported that FTY720 has protective effect on intracerebral hemorrhage-induced secondary neurological damage in rats [24]. Besides, in the rodent model of autism, FTY720 improved short-term memory in 8-arm radial maze test [26], indicating that FTY720 possesses potent neuroprotective activity. FTY720 alleviated the symptoms of ischemia/reperfusion injury in animal model and reduced IL-23 levels in brain tissues [21]. Nevertheless, the underlying mechanism how FTY720 exerts protective effect on brain remains incompletely understood and application of FTY720 in treatment of cerebral ischemia/reperfusion injury would be worth investigating further.
Inflammatory cytokines play crucial roles during cerebral ischemia–reperfusion, especially in the acute phase within 24 h [26], [38]. p38MAPK (mitogen-activated protein kinase, MAPK) signaling pathway was activated in ischemic brain tissue and p38MAPK phosphorylation was implicated in the activation of inflammatory response [12], [20]. Previous work suggested that p38MAPK activity was increased in microglia of the hippocampus, and p38MAPK inhibitors effectively reduced neuronal death in rats undergoing bilateral common carotid artery ligation (BCCAL), followed by reperfusion for 7 min [36], [37]. The purpose of this study is to investigate whether FTY720 improves neurological deficits and reduces neuronal apoptosis in rodent model of middle cerebral ischemia reperfusion, and whether this protective effect is associated with p38MAPK and NF-κB signaling pathways.
In this study, using a rat model of middle cerebral ischemia reperfusion caused by bilateral common carotid artery ligation, we found that FTY720 improved the neurological deficits, reduced neuronal damage and decreased the release of inflammatory cytokines (IL-1β, IL-6, and TNF-α). Given the neuroprotective activity of FTY720, it may be a potential therapeutic agent for patients with ischemia reperfusion injury-associated tissue inflammation and organ dysfunction.
Section snippets
Animals
Sprague-Dawley (SD) rats (250–300 g, N = 76 rats in total, male) were purchased from the Experimental Animal Center of Jinzhou Medical University and housed under specific-pathogen free (SPF) condition with access to food and water ad libitum (temperature 22–24 °C, relative humidity 45–55%, and12:12 h light‐dark cycle). All Animal experiments were approved by the Ethics Committee of Jinzhou Medical University.
Rat model of transient cerebral ischemia/reperfusion (tMCAO/R)
Cerebral ischemia was generated by transient middle cerebral artery occlusion (tMCAO).
FTY720 improves neurological deficits of SD rats undergoing cerebral ischemia reperfusion injury
In present study, experimental workflow is represented in Fig. 1A. We found that neurological score in the operated groups was significantly increased compared with sham-operated groups, suggesting we successfully construct cerebral ischemia reperfusion injury rat model (Fig. 1B, 1C). When rats were administrated with two different doses of FTY720 before tMACO/R, neurological scores in FTY720-pretreatment groups were significantly lower than that in the operated group in a dose-dependent manner
Discussion
In the present study, FTY720 was applied to interfere with the progression of cerebral ischemia reperfusion injury in rats. Based on a rat cerebral ischemia–reperfusion injury model, data showed that the neurological score of rats in the FTY720 pretreatment or post-treatment group was significantly lower than that in the operated group at days 7, indicating that FTY720 could improve neurological symptoms caused by ischemia and reperfusion. Additionally, FTY720 administration before or after
Conclusion
In summary, our findings suggested that FTY720 ameliorated neurological deficit of rat cerebral ischemia reperfusion model and reduced neuronal damage in the ischemic brain., FTY720 treatment down-regulated the expression levels of inflammatory factors including IL-1β, IL-6 and TNF-α, and inhibited the activation of P38 MAPK and NF-κB signaling pathways. FTY720 holds promise as an attractive therapeutic drug for alleviating ischemic perfusion injury.
Authors’ contributions
Ling Zhang, Rubo Sui and Lei Zhang contributed to the animal model performance, collection and assembly of data, and drafting the manuscript. Rubo Sui and Lei Zhang involved in experimental design, interpretation of data, critical revision of the manuscript. All authors read and approved the final manuscript.
Ethics approval
All rats were obtained from the Laboratory Animal Center of Jinzhou Medical University. All animal procedures followed the National Institutes of Health’s Guide for the Care and Use of Laboratory Animals. All protocols were approved on accordance of the Committee on Animal Research of Jinzhou Medical University.
Declaration of Competing Interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Acknowledgments
Not applicable.
Funding
This work was supported by the National Natural Science Foundation of China (Grant No. 81371461), Fund from Liaoning Education Department (Grant No. JYTQN201707), the Natural Science Foundation of Liaoning Province (Grant No. 2019-ZD-0802), and the Natural Science Foundation of Liaoning Provincial Department of Education (Grant No. JYTJCZR201903; Grant No. JYTJCZR2020065).
Availability of data and materials
The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.
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